Crossrail, the Channel Tunnel rail link, basement developments – underground London is growing as fast as the surface city.
The past, present and future of our subterranean spaces are celebrated in the latest exhibition at New London Architecture.
To be honest, you can enjoy most of the show from the comfort of your laptop by downloading the guide.
However, if you're in the Tottenham Court Road area, it's worth popping in to see the model of subterranean King's Cross. It's a tangled web down there. As well as Tube lines and Thameslink, the River Fleet flows past in its own conduit. And what's that mysterious 'other tunnel' running the length of York Way?
While you're there, check out the gallery of 'small projects', designs for the Olympic velopark and an update on Tegs Farrell's 'Manifesto for London'.
Underground: London's Hidden Infrastructure runs till 19 April. New London Architecture is at 26 Store Street.